This older Allegheny did not run smooth when I got it. The motor would hum and the engine seemed to struggle to start moving. Then it would take off too fast for my tastes. I checked the drive train and nothing seemed wrong.
The engine is now upgraded to MTH's Ps2 control boards and smoke unit. Of course the smoke is crazy good now and timed to the drivers. I'll need to change the smoke unit to one for double stacks. This one came out of a Railking starter engine.
What surprised me is how much better the engine performs. No more motor noise. It now runs smoothly. I thought these 3rd Rail engines weren't living up to what I expected. I had wondered if their drives were tougher to run at slow speeds. I'm quite happy now with their performance.
Here's a quick video: